Jump-spark ignition-plug.



l PATENTED OCT. zo, 190s; lJ'. -H'fLEHM/AN. JUMP SPARK IGNITION PLUG. APPLOTION FILED PEB. 6\ 1902.

No MODEL.

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UNITED STATES Patented October 20, 190?.

' JOSEPH H. LEHMAN, oF NEW YORK, N. Y.

JUMP-SPARK IG NvlTI-ON-QPLUG.

SPECIFICATION forming part of Letters Patent N o. 741,684, dated October 20, 1903. Application filed February 6, 1902. Serial No. 92.791. (No model.)

the power medium utilized, as gas, is duly' ignited through the production at proper intervals within such cylinder or chamber containing such power medium of an electric jump-spark effect, the same being commonly known as jumpspark ignition-plugs.

The object of this'invention is -to provide an ignition-plugof the character aforenamed which shall be sim ple, inexpensive, and novel as regards construction, which shall embody features of construction whereby shall be minimized the accumulation of products of combustion, lubricating'elements, and the like at or upon points or surfaces of the plug where the same would operate to curtail or detract from the efficiency of the plug, thus insuring the maintenance of the normal or maximum efficiency of the plug practically throughout the life thereof, which shall be so constructed as to insure marked convenience to the user in gaining access to the va-v rious parts thereof when desired, and which shall possess certain well-defined advantages y over prior analogous constructions.

The invention consists of certain novel constructions and combinations hereinafter described, and pointed out in the claims.

The invention is clearly illustrated in the accompanying drawings, wherein similar reference-numerals denote like parts throughoutthe several views.

In said drawings, Figure 1 is an elevation of an ignition-plug embodying my said improvements, a fragment of an engine-cylinder being shown in connection therewith to better disclose the practical application thereof. Fig. 2 is a' central longitudinal section taken as along the line ct a, of Fig. 3. Fig. 3 is a bottom plan View of the plug, the same being intended to more clearly illustrate the construction and relative disposition -of the primary and secondary caps which I employ as elements of my improved ignition-plug. Fig. 4 is a' detail view illustratinga modification of my improved plug, the view being v partly in section.

Reference being had to the accompanying drawings, 2 denotes a casing which is of metal or other suitable conductor of electricity and has a screw-threaded portion 8, adapted to be screwed into a correspondingly-.threaded opening in the cylinder 4, Fig. 1, of an eX- plosion-engine. On that end of -the casing is a cap 5, which in the present instance is integral with the oasing,'they end of which cap is provided with a small perforation 5, preferably concentric with t-he cap, as shown. 6 is an insulating-core within said casing, of porcelain, lava, or other suitable non-conductingk material. It is shaped to rest against a shoulder 6', formed Within the casing, or against suitable packing 7 at said shoulder. It is held inposition within` the casing by means of a sleeve or nut 7. upon the core,

this sleeve being screw-threaded and screwed into the end of the case, which is provided with corresponding threads, as seen in Fig. 2. I usually interpose a suitable packing 8 between the inner end of the said sleeve and a shoulder ot the core.

8 is a bar of metal or other suitable conductor of electricity that extends longitudinally through the core. This bar, which will behereinafter termed the circuit-terminal, is detachably secured within the core by means of a collar 8 and a threaded nut 9 -on the end of t-he bar that projects from the casing, lche said collar stopping against the end portion of the corel when the nut is screwed up against the core. I sometimes interpose a cap 9 and a check-nut 9" between nut Sand thelcore. The circuit-terminal is preferably made tapering to a point from the bearing ofthe said collar, which point registers substantially with and is adjacent to the perforation 5 of the'cap, as clearly shown in Fig. 2. In the casing 2 is a chamber with which the ,perforation 5 directly communicates. This chamber is formed in the present instance as follows: The core is extended into the cap, with its free extremity but a short distance from the end of the said IOO cap, and this end is provided with a longitudinal concavity or recess lO, which is prefer- .ably conical, as seen in Fig. 2, while the peripheral part of said end of the core tapers forward away from the side of the casing, as also shown in said figure. Thus a space 10 is formed between that part of the core and the casing, which space communicates with the recess l0 between the end of the core and the cap, said space and recess forming practically a single chamber into which the gas will enter from the engine-cylinder solely by way of the perforation 5 of the cap when the engine is in operation. By the construction just described I not only secure a chamber Within said cap for a purpose of my invention hereinafterexplained, but I obtain other important advantages that will hereinafter appear.

Having thus described the construction of my invention, I shall now describe the mode of operation and the advantages thereof, as follows: The plug is applied to the cylinder of the engine, as in Fig. l, and is connected with a source of electrical energy in the manner usual with devices of the same general character, a suitable controller being employed to close and break the circuit at predetermined times. Vhen the circuit is broken, a sparking occurs between the free end or point of the circuit-terminal Sand the wall of the perforation 5 of the cap. This sparking is made to take place when the piston of the engine is adjacent tothe plug. Simultaneously with the ignition or explosion of the gaseous mixture within the engine-cylinder 4c induced by the sparking ignition and explosion of the mixture within the chamber 10 lO occurs. As the piston moves back by the force of the explosion within the cylinder the gas or a portion of it within said chamber, being relieved to a certain extent of pressure, rushes out through the perforation 5' and in doing so blows off any burned oil or unconsumed charge that may be deposited upon the Wall of said perforation and also such as may be deposited on the point of the circuit-terminal 8'. Thus these important surfaces are kept clean and bright, thereby insuring the certainty of the sparking action so long as the other parts of the plug remain in proper working condition. On the return movement of the engine-piston-i. c., toward the end of the cylinder in which the plug is inserteda portion of any burned oil or unconsumed charge within said cylinder will or may be forced into the cup through the perforation 5'; but obviously such burned oil, dsc., cannot form a bridge between the circuit-terminal and the side of the cap unless and until it (any burned oil, zc., that may be deposited and accumulate upon the core) shall extend continuously along the Wall of the recess lO, from the bottom to the mouth thereof, and thence along the outside of the core to the side of the cap 5. It is manifestly desirable that such continuity of the accumulation shall be prevented or at least that it be so delayed that the same cannot occur except at such long intervals of time as to be of little practical importance. Now as the perforation 5 of the cap is in direct line with the recess lO of the core and the mouth of the recess is but a short distance from the end of the cap, as shown, the burned oil, die., that may be forced through said perforation will pass directly into the recess, only a comparatively small quantity thereof going into the outer space 10.

I have had several of my plugs constructed substantially as hereinbefore described in almost dailypractical use for a period of many months and have found, on examination of the same, the outer side of the end of the core Within the cap to be practically free from any deposit of burned oil or other deleterious matter, there being but a small quantity of the same at and adjacent to the free end. I further found that the deposit within the recess lO extended inwardly from the mouth of the recess; but there was considerable space from the bottom of the latter that was entirely devoid of such deposit. I may also state that I found the pointed end of the circuitterminal and the walls of the perforation of the cap 5 to be entirely devoid of any deposit of matter. Ifand when in the course of time sufficient of said matter should accumulate upon the core to form a bridge, it (the core) may be readily detached from the casing and the deposit removed. By making the end of the core recessed and offsetting the same from the side of the cap, as shown and described, I obtain a very considerable area or distance that must be coated with the burned oil, dac., before a bridge can be formed. By making said recess conical and the outer side of the core tapering I not only secure the desired suitable chamber Within the cap, but the wall of the recessed end of the core is made comparatively thick and strong except at the extreme end. Consequently there is little, if any, liability of fracture of said wall from the force of explosion of the gaseous mixture.

I sometimes attach to the cap 5 a supplemental cap 10, having an orifice ll near the side that is out of registry with the perforation 5 in cap 5, a space being left between the two caps, as shown in Figs. 2 and 4. The purpose of this supplemental cap is to prevent in a measure the burned oil, duc., from reaching and passing through the perforation 5 of the inner cap.

In Fig. 4C I have shown a slightly-modified form of my device, the modification consisting in so arranging the casing 2 and the cap 5 that the latter may be readily applied to or removed from the casing, the said cap having a screw-threaded connection with the casing.

Having thus described my invention, I claim as new and desire to secure by Letters Patent-n 1. In a jump-spark ignition-plug, the com IOO IIO

bination of the casing, the cap on thev end thereof, having the perforation, the insulating-core extending into and adjacent to the end of said cap and having the longitudinal recess with Which said perforation communicates, together with the conductor-terminal within said core extending through said recess, and having its free end substantially in registry with and extending into said perforation of the cap and maintained out of contact with the latter, substantially as and for the purpose set forth.

2. In a device of the character recited, the combination of the casing, the cap on the end thereof having the perforation, the insulating-core extending into said cap, and having its freeend portion adjacent to the end thereof and having the longitudinal recess with which said perforation communicates, the side of said free end portion being separated from the said cap, to form a space communicating with said recess, together with the conductor-terminal extending through said Arecess and having its free end substantially `in registry with and adjacent to said perforation of the cap, substantially as and for the purpose set forth.

3. In a device of the character recited, the combination-of the casing, the cap on the end extends, and having also the end perforation communicating With said chamber, the conductor-terminal'within said core and having its free end substantially in registry with and adjacent to said perforation, together with the supplemental cap having the perforation out of registry with the perforation of said other cap, there being a space between the said caps with which the said perforations of said caps communicate, substantially as and for the purpose set forth. f

JOSEPH H. LEI-IMAN.

Witnesses:

JOHN BERGESEN, W. H. RUBY. 

